U.S. patent number 5,618,901 [Application Number 08/387,303] was granted by the patent office on 1997-04-08 for process for making a high nitrile multipolymer prepared from acrylonitrile and olefinically unsaturated monomers.
This patent grant is currently assigned to The Standard Oil Company. Invention is credited to Lawrence E. Ball, Richard C. Smierciak, Eddie Wardlow, Jr..
United States Patent |
5,618,901 |
Smierciak , et al. |
April 8, 1997 |
Process for making a high nitrile multipolymer prepared from
acrylonitrile and olefinically unsaturated monomers
Abstract
A homogeneous, high nitrile melt processable acrylonitrile
olefinically unsaturated multipolymer and a process for making the
multipolymer, comprising polymerizing a mixture of acrylonitrile
monomer and one or more olefinically unsaturated monomers, in which
the rate of addition of the multimonomer mixture is set by the rate
of polymerization so that the concentration of unreacted
acrylonitrile monomers and unreacted olefinically unsaturated
monomer(s) is low and the polymerization process is in a monomer
starved condition.
Inventors: |
Smierciak; Richard C. (Aurora,
OH), Wardlow, Jr.; Eddie (Shaker Hts., OH), Ball;
Lawrence E. (Akron, OH) |
Assignee: |
The Standard Oil Company
(Cleveland, OH)
|
Family
ID: |
23529296 |
Appl.
No.: |
08/387,303 |
Filed: |
February 27, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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150515 |
Nov 10, 1993 |
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Current U.S.
Class: |
526/342 |
Current CPC
Class: |
C08F
220/44 (20130101) |
Current International
Class: |
C08F
220/44 (20060101); C08F 220/00 (20060101); C08F
220/48 () |
Field of
Search: |
;526/342 |
References Cited
[Referenced By]
U.S. Patent Documents
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2692875 |
October 1954 |
Weinstock, Jr. et al. |
3565876 |
February 1971 |
Ball et al. |
4577008 |
March 1986 |
Benton et al. |
4719150 |
January 1988 |
Huber et al. |
5106925 |
April 1992 |
Curatolo et al. |
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Foreign Patent Documents
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1147040 |
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Apr 1963 |
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DE |
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46-3071 |
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Jan 1971 |
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JP |
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49-67987 |
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Jul 1974 |
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JP |
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1260016 |
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Oct 1989 |
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JP |
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823345 |
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Nov 1959 |
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GB |
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Primary Examiner: Schofer; Joseph L.
Assistant Examiner: Sarofim; N.
Attorney, Agent or Firm: Untener; David J. Esposito; Michael
F. Gilbert; Teresan W.
Parent Case Text
RELATED APPLICATION
This patent application is a continuation-in-part to patent
application entitled "A PROCESS FOR MAKING A POLYMER OF
ACRYLONITRILE, METHACRYLONITRILE AND OLEFINICALLY UNSATURATED
MONOMERS", U.S. Ser. No. 08/150,515 and filed on Nov. 10, 1993
abandoned. It is understood that the term multipolymer herein
includes copolymers, terpolymers and multipolymers throughout the
specification.
Claims
What is claimed:
1. A process for polymerizing an acrylonitrile monomer and one or
more olefinically unsaturated monomers to make an acrylonitrile
olefinically unsaturated multipolymer, said process comprising the
steps of:
heating an initial multimonomer mixture comprising acrylonitrile
monomer and one or more olefinically unsaturated monomer, under an
inert atmosphere, in the range of about 30.degree. C. to about
120.degree. C.;
adding an initiator to the initial multimonomer mixture to start a
polymerization reaction;
adding a multimonomer feed mixture comprising acrylonitrile monomer
and olefinically unsaturated monomer(s) to the polymerization
mixture wherein the multimonomer feed mixture contains about 50% by
weight to about 95% by weight acrylonitrile monomer and about 5% by
weight to about 50% by weight olefinically unsaturated monomer(s),
wherein the multimonomer feed mixture has a fixed and constant
molar ratio of acrylonitrile monomer to olefinically unsaturated
monomer(s); and wherein the rate of addition of the multimonomer
feed mixture is less than or equal to the rate of
polymerization.
2. The process of claim 1 wherein a molecular weight modifier is
added to the initial multimonomer mixture, to the multimonomer feed
mixture or to both mixtures in the range of about 0% by weight to
about 5% by weight of total multimonomer mixture and is selected
from the group consisting of mercaptans, alcohols, halogen
compounds and combinations thereof.
3. The process of claim 2 wherein the molecular weight modifier is
a mono-mercaptan, a multifunctional mercaptan or combinations
thereof and further wherein the mercaptan is selected from the
group consisting of C.sub.5 to C.sub.18 alkyl mercaptans which are
straight chained, branched, substituted, unsubstituted and
combinations thereof.
4. The process of claim 3 wherein the mercaptan is selected from
the group consisting of t-dodecyl mercaptan, n-octyl mercaptan,
d-limonene dimercaptan and combinations thereof.
5. The process of claim 1 wherein the initial multimonomer mixture
is heated from about 50.degree. C. to about 80.degree. C.
6. The process of claim 1 wherein the initiator is added to the
initial multimonomer mixture in the range of 0.01% by weight to
about 5% by weight of total multimonomer mixture and is selected
from the group consisting of azo compounds, peroxides,
hydroperoxides, alkyl peroxides, peroxydicarbonates, peroxyesters,
dialkyl peroxides, persulfates, perphosphates and combinations
thereof.
7. The process of claim 1 further comprising the step of adding an
initiator continuously to the polymerization reaction media and
wherein the initiator is added to the polymerization reaction media
at about 0.01% by weight to about 5% by weight of total
multimonomer mixture and is further selected from the group
consisting of azo compounds, peroxides, hydroperoxides, alkyl
peroxides, peroxydicarbonates, peroxyesters, dialkyl peroxides,
persulfates, perphosphates and combinations thereof.
8. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated
monomer present in the polymerizing mixture, at any time, is not
greater than about 15% by weight of the polymerizing mixture.
9. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated
monomer present in the polymerizing mixture, at any time, is not
greater than about 10% by weight of the polymerizing mixture.
10. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated
monomer present in the polymerizing mixture, at any time, is not
greater than about 5% by weight of the polymerizing mixture.
11. The process of claim 1 wherein said process is carried out as
an emulsion, a solution, a suspension or in continuous addition
bulk.
12. The process of claim 1 wherein the olefinically unsaturated
monomer is selected from the group consisting of acrylates,
methacrylates, acrylamides, methacrylamides, acrylamide
derivatives, methacrylamide derivatives, vinyl esters, vinyl
ethers, vinylamides, vinyl ketones, styrenes, halogen containing
monomers, ionic monomers, acid containing monomers, base containing
monomers, olefins and combinations thereof.
13. The process of claim 12 wherein the olefinically unsaturated
monomer is selected from the group consisting of methyl acrylate,
ethyl acrylate, methyl methacrylate, vinyl acetate, styrene,
.alpha.-methyl styrene, indene, vinyl bromide, vinylidene chloride,
sodium vinyl sulfonate, sodium styrene sulfonate, sodium methallyl
sulfonate, itaconic acid, styrene sulfonic acid, vinyl sulfonic
acid, isobutylene, ethylene, propylene and combinations
thereof.
14. The process of claim 12 wherein the olefinically unsaturated
monomer is selected from the group consisting of .alpha.-methyl
styrene, methyl acrylate, methyl methacrylate, styrene, vinyl
acetate and combinations thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a homogeneous acrylonitrile
olefinically unsaturated multipolymer and a process to make the
same. This multipolymer has molecularly uniform monomer sequences
throughout the multipolymer, has a high nitrile polymer content and
is melt processable. More specifically, the invention relates to a
monomer starved process for producing an acrylonitrile olefinically
unsaturated multipolymer in which the polymerization rate exceeds
or equals the addition rate of the multimonomers of acrylonitrile
monomers and olefinically unsaturated monomer(s).
2. Description of the Prior Art
Acrylic polymers are high nitrile polymers which are desirable in
the production of fibrous textiles, films, molded objects,
packaging applications and the like. High nitrile polymers have
excellent physical, thermal and mechanical properties such as
barrier properties, chemical resistance, rigidity, heat resistance,
UV resistance, moisture retention and bacteria resistance.
However, acrylic polymers and multipolymers having long repeating
sequences of acrylonitrile monomer units are known to degrade when
heated and processed by commercial methods. The long sequences of
nitrile units make the acrylic high nitrile polymers
non-processable without the use of solvent.
Thermoplastic nitrile barrier polymer resins are known in the art
and have been described in U.S. Pat. Nos. 3,426,102 and 3,586,737.
These nitrile polymers are known to have desirable barrier
properties and chemical resistance. However, these thermoplastic
nitrile polymers while melt processable are difficult to
process.
U.S. Pat. No. 5,106,925 discloses a thermoplastic nitrile polymer.
However, the process to produce the nitrile polymer is based on
tracking the polymer conversion and adding the reactants in the
same mount as they are removed and converted to polymer. This
process must make proper adjustments in rates and quantities
throughout the polymerization process.
It is desirable to produce thermoplastic high nitrile multipolymers
by a process in which the nitrile monomer units are uniformly
sequenced throughout the chain. It is advantageous to produce a
homogeneous acrylonitrile olefinically unsaturated multipolymer
with improved thermoplastic properties and a high nitrile content
which multipolymers are melt processable in the absence of a
solvent. It is an object of the invention to make a nitrile polymer
chain with uniformly sequenced and short sequences of the nitrile
monomer in a process that has a fixed monomer feed ratio.
SUMMARY OF THE INVENTION
The present invention provides a new melt-processable multipolymer
comprising about 50% to about 95% polymerized acrylonitrile and
about 5% to about 50% polymerized olefinically unsaturated monomer
which is melt-processable and contains relatively uniform
distribution of monomers in the multipolymer chain.
The present invention provides a new and an improved process for
producing an acrylonitrile olefinically unsaturated multipolymer
with improved thermal stability, excellent mechanical and excellent
physical properties. The process comprises polymerizing an
acrylonitrile monomer and one or more olefinically unsaturated
monomers in which the rate of addition of the acrylonitrile monomer
and the olefinically unsaturated monomer(s) is set to be equal to
or less than the rate of polymerization to maintain a monomer
starved process. Further, the weight of unreacted acrylonitrile
monomer and unreacted olefinically unsaturated monomer(s) is not
greater than 15% of the weight of the polymerizing mixture.
Further, the molar ratio of acrylonitrile monomer and olefinicaily
unsaturated monomer(s) is fixed and constant for the multimonomer
feed throughout the polymerization process and the multipolymer
product ratio is similar to the multimonomer feed ratio.
The present invention provides in particular, a process for
polymerizing an acrylonitrile monomer and one or more olefinically
unsaturated monomers to make an acrylonitrile olefinically
unsaturated multipolymer, said process comprising the steps of:
heating an initial multimonomer mixture comprising acrylonitrile
monomer and one or more olefinically unsaturated monomer, under an
inert atmosphere, in the temperature range of about 30.degree. C.
to about 120.degree. C.;
adding an initiator to the initial multimonomer mixture to start a
polymerization reaction;
adding a multimonomer feed mixture comprising acrylonitrile monomer
and olefinically unsaturated monomer(s) to the polymerization
mixture wherein the multimonomer feed mixture contains about 50% by
weight to about 95% by weight acrylonitrile monomer and about 5% by
weight to about 50% by weight olefinically unsaturated monomer(s),
wherein the multimonomer feed mixture has a fixed and constant
molar ratio of acrylonitrile monomer to olefinically unsaturated
monomer(s), wherein the rate of addition of the multimonomer feed
mixture is less than or equal to the rate of polymerization
resulting in a homogeneous acrylonitrile olefinically unsaturated
multipolymer product; wherein the acrylonitrile olefinically
unsaturated multipolymer produced is about 50% by weight to about
95% by weight polymerized acrylonitrile monomer and about 5% by
weight to about 50% by weight polymerized olefinically unsaturated
monomer(s) and wherein said multipolymer is thermally stable and
melt processable without the use of solvents.
The process of the present invention produces a thermoplastic
homogeneous acrylonitrile olefinically unsaturated multipolymer in
which short sequences of acrylonitrile monomer and short sequences
of olefinically unsaturated monomer(s) are interdispersed randomly
throughout the polymerized chain resulting in a thermally stable
melt processable multipolymer with improved characteristics. The
acrylonitrile olefinically unsaturated multipolymer is melt
processable in the absence of solvent or plasticizing agent to
produce high nitrile products.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a homogeneous, melt processable
high nitrile multipolymer prepared from polymerizing an
acrylonitrile monomer and one or more olefinically unsaturated
monomers and the process to produce the multipolymer.
The new and improved process for producing a thermally stable, melt
processable multipolymer from acrylonitrile monomer and
olefinically unsaturated monomer(s) is accomplished by controlling
the rate of addition of the acrylonitrile monomer and the
olefinically unsaturated monomer(s) relative to the rate of
polymerization. The process of the invention is a monomer starved
process in which the polymerization reaction rate exceeds or equals
the multimonomer feed mixture addition rate. The low concentration
of the unreacted multimonomers during the polymerization step
generates a monomer starved condition which prevents long sequences
of acrylonitrile monomer in the multipolymer. The multipolymer
contains short sequences of polymerized olefinicaily unsaturated
monomer interdispersed between short sequences of polymerized
acrylonitrile monomer for example, AN-AN-X-AN-AN-X-X- AN-X -X
(AN=acrylonitrile unit and X=olefinically unsaturated unit),
allowing for melt processability of the high nitrile thermoplastic
acrylonitrile olefinically unsaturated multipolymer in the absence
of solvent.
The rate of addition of the acrylonitrile monomer and the
olefinically unsaturated monomer(s) is continuous throughout the
polymerization reaction. The molar ratio of the multimonomer feed
mixture of acrylonitrile monomer and olefinically unsaturated
monomer(s) is constant and fixed throughout the process. The
process produces a homogeneous composition of a thermoplastic high
nitrile multipolymer similar to the molar ratio of the incoming
multimonomer feed mixture. The multipolymer material made in the
early part of the process is substantially similar to the
multipolymer material made at the end of the process, meaning there
is no major shift either in composition or sequencing of the
multipolymers, resulting in a homogeneous multipolymer product.
The thermoplastic high nitrile multipolymer that is produced by the
process of the instant invention comprises about 50% to about 95%,
preferably about 65% to about 90% and most preferably about 70% to
about 90% of polymerized acrylonitrile monomer, and about 5% to
about 50%, preferably about 10% to about 35% and most preferably
about 10% to about 30% of polymerized olefinically unsaturated
monomer(s).
The olefinically unsaturated monomer employed in the present
invention is one or more of any olefinically unsaturated monomer
with a C=C double bond polymerizable with an acrylonitrile monomer.
The olefinically unsaturated monomer employed in the multimonomer
mixture can be a single polymerizable monomer resulting in a
copolymer or a combination of polymerizable monomers resulting in a
terpolymer or a multipolymer.
The olefinically unsaturated monomer generally includes but is not
limited to acrylates, methacrylates, acrylamide and its
derivatives, methacrylamide and its derivatives, vinyl esters,
vinyl ethers, vinyl aides, vinyl ketones, styrenes, halogen
containing monomers, ionic monomers, acid containing monomers, base
containing monomers, olefins and the like.
The acrylates include but are not limited to C.sub.1 to C.sub.12
alkyl, aryl and cyclic acrylates such as methyl acrylate, ethyl
acrylate, phenyl acrylate, butyl acrylate and isobornyl acrylate,
2-ethylhexyl acrylate and functional derivatives of the acrylates
such as 2-hydroxyethyl acrylate, 2-chloroethyl acrylate and the
like. The preferred acrylates are methyl acrylate and ethyl
acrylate.
The methacrylates include but are not limited to C.sub.1 to
C.sub.12 alkyl, aryl and cyclic methacrylates such as methyl
methacrylate, ethyl methacrylate, phenyl methacrylate, butyl
methacrylate, isobornyl methacrylate, 2-ethylhexyl methacrylate and
functional derivatives of the methacrylates such as 2-hydroxyethyl
methacrylate, 2-chloroethyl methacrylate and the like. The
preferred methacrylate is methyl methacrylate.
The acrylamides and methacrylamides and each of their N-substituted
alkyl and aryl derivatives include but are not limited to
acrylamide, methacrylamide, N-methyl acrylamide, N,N-dimethyl
acrylamide and the like.
The vinyl esters include but are not limited to vinyl acetate,
vinyl propionate, vinyl butyrate and the like. The preferred vinyl
ester is vinyl acetate.
The vinyl ethers include but are not limited to C.sub.1 to C.sub.8
vinyl ethers such as ethyl vinyl ether, butyl vinyl ether and the
like.
The vinyl amides include but are not limited to vinyl pyrrolidone
and the like.
The vinyl ketones include but are not limited to C.sub.1 to C.sub.8
vinyl ketones such as ethyl vinyl ketone, butyl vinyl ketone and
the like.
The styrenes include but are not limited to methylstyrenes,
styrene, indene, a styrene of the formula: ##STR1## wherein each of
A, B, C, and D is independently selected from hydrogen (H) and
C.sub.1 to C.sub.4 alkyl groups, substituted styrenes,
multiply-substituted styrenes and the like.
The halogen containing monomers include but are not limited to
vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride,
vinylidene bromide, vinylidene fluoride, halogen substituted
propylene monomers and the like. The preferred halogen containing
monomers are vinyl bromide and vinylidene chloride.
The ionic monomers include but are not limited to sodium vinyl
sulfonate, sodium styrene sulfonate, sodium methallyl sulfonate,
sodium acrylate, sodium methacrylate and the like. The preferred
ionic monomers are sodium vinyl sulfonate, sodium styrene sulfonate
and sodium methallyl sulfonate.
The acid containing monomers include but are not limited to acrylic
acid, methacrylic acid, vinyl sulfonic acid, itaconic acid, styrene
sulfonic acid and the like. The preferred acid containing monomers
are itaconic acid, styrene sulfonic acid and vinyl sulfonic
acid.
The base containing monomers include but are not limited to vinyl
pyridine, 2-aminoethyl-N-acrylamide, 3-aminopropyl-N-acrylamide,
2-aminoethyl acrylate, 2-aminoethyl methacrylate and the like.
The olefins include but are not limited to isoprene, butadiene,
C.sub.2 to C.sub.8 straight chained and branched alpha-olefins such
as propylene, ethylene, isobutylene, diisobutylene, 1-butene and
the like. The preferred olefins are isobutylene, ethylene and
propylene.
The olefinically unsaturated monomer does not include nitrile
monomers such as methacrylonitrile. The acrylonitrile olefinicaily
unsaturated multipolymer does not contain methacrylonitrile.
The choice of olefinically unsaturated monomer or combination of
monomers depends on the properties desired to impart to the
resulting high nitrile multipolymer and its end use. For instance,
polymerizing monomers of acrylonitrile and styrene and/or indene
results in a high nitrile multipolymer and its end products with
improved heat distortion temperature and glass transition
temperature. Polymerizing monomers of acrylonitrile and isobutylene
improves the flexibility of the high nitrile multipolymer and its
end products. Polymerizing monomers of acrylonitrile and acrylates
and/or methacrylates improves the processability of the high
nitrile multipolymer and its end products. Polymerizing
acid-containing monomers, base containing monomers and/or hydroxyl
group containing monomers with an acrylonitrile monomer provides
useful dye sites which enhance the colorability of the resulting
high nitrile multipolymer. Polymerizing monomers of acrylonitrile
and a halogen containing monomer increases the flame resistance of
the high nitrile multipolymer and its end products.
In the practice of the present invention the polymerization process
is carried out as an emulsion, a solution, a suspension or in
continuous addition bulk. Preferably, the polymerization process is
carried out as an emulsion or a suspension. The present invention
can be practiced as a semibatch or continuous process. The process
of the present invention is not carried out as a batch process
which batch process is defined herein as a process in which all the
reactants are charged initially to the reaction vessel prior to the
initiation of polymerization.
Initially, acrylonitrile monomer and olefinically unsaturated
monomer(s) are contacted in an aqueous medium at about 0.1% by
weight to about 15% by weight of the total polymerization reaction
media. The initial multimonomer mixture contains about 50% by
weight to about 95% by weight acrylonitrile monomer and about 5% by
weight to about 50% by weight olefinically unsaturated
monomer(s).
The aqueous medium contains water and a suitable surfactant such as
an emulsifier or a dispersing agent. The surfactants and their uses
are known to those skilled in the art.
A molecular weight modifier may be added to the initial
multimonomer mixture in the range of about 0% by weight to about 5%
by weight, preferably about 0.1% by weight to 4% by weight and most
preferably about 0.1% by weight to about 3% by weight of the total
multimonomer mixture.
The initial multimonomer mixture is placed into a reaction vessel
containing aqueous medium. The reaction vessel with the aqueous
medium is purged with an inert gas, such as nitrogen, argon and the
like. Preferably, but optionally, the inert gas purge is continued
throughout the polymerization reaction. The initial multimonomer
mixture is then heated to a temperature in the range of about
30.degree. C. to about 120.degree. C., preferably about 40.degree.
C. to about 100.degree. C. and most preferably about 50.degree. C.
to about 80.degree. C. The temperature of the polymerization
reaction is maintained throughout the process in the range of about
30.degree. C. to about 120.degree. C., preferably about 40.degree.
C. to about 100.degree. C. and most preferably about 50.degree. C.
to about 80.degree. C.
An initiator is added to the heated initial multimonomer mixture to
start the polymerization reaction. The initiator is added generally
in the range of about 0.01% by weight to about 5% by weight of the
total multimonomer mixture.
After the polymerization reaction commences, a multimonomer feed
mixture of acrylonitrile monomer and olefinically unsaturated
monomer(s) is continuously added to the polymerization reaction in
the reaction vessel. The combined weight of the unreacted
acrylonitrile monomer and unreacted olefinically unsaturated
monomer(s) present in the polymerizing mixture, at any time, is not
greater than about 15% by weight, preferably not greater than about
10% by weight, and most preferably not greater than about 5% by
weight of the polymerizing mixture.
The multimonomer feed mixture contains about 50% by weight to about
95% by weight acrylonitrile monomer, and 5% by weight to about 50%
by weight olefinically unsaturated monomer(s). The molar ratio of
the acrylonitrile monomer and the olefinically unsaturated
monomer(s) in the multimonomer feed mixture, is fixed and constant
throughout the polymerization process resulting in a homogeneous
multipolymer. The feed molar ratio of the acrylonitrile monomer to
olefinically unsaturated monomer depends on the desired
acrylonitrile, olefinically unsaturated multipolymer composition.
The multipolymer composition is similar to the composition of the
multimonomer feed mixture.
A molecular weight modifier is optionally added to the
polymerization mixture. Preferably, a molecular weight modifier is
employed in the polymerization mixture. The molecular weight
modifier is added continuously or incrementally to the
polymerization mixture. Preferably, the molecular weight modifier
is added continuously to the polymerization mixture. The molecular
weight modifier is preferably added to the polymerization reaction
media in the range of about 0% by weight to about 5% by weight,
preferably about 0.1% by weight to about 4% by weight, and most
preferably about 0.1% by weight to about 3% by weight of the total
multimonomer mixture.
The molecular weight modifier includes but is not limited to
mercaptans, alcohols, halogen compounds or any other chain transfer
agent known to those skilled in the art. Mercaptans are the
preferred molecular weight modifier and include mono-mercaptans,
multifunctional mercaptans or combinations thereof. The mercaptans
include but are not limited to C.sub.5 to C.sub.18 alkyl mercaptans
whether straight chained, branched, substituted or unsubstituted,
d-limonene dimercaptan, dipentene dimercaptan and the like. The
preferred mercaptans are the C.sub.5 to C.sub.12 alkyl mercaptans
whether straight chained, branched, substituted or unsubstituted,
for example t-dodecyl mercaptan and n-octyl mercaptan. The
molecular weight modifier can be employed singularly or in
combination. The molecular weight modifier can be the same or a
different molecular weight modifier as is employed with the initial
multimonomer mixture.
The molecular weight modifier controls the molecular weight of the
polymerized acrylonitrile olefinically unsaturated multipolymer
chain by terminating the growing chain. The molecular weight
modifier useful in the present invention produces an acrylonitrile,
olefinically unsaturated multipolymer with a molecular weight in
the range of about 15,000 molecular weight to about 500,000
molecular weight.
The initiator is added typically as a single solution, continuously
or incrementally, to the polymerization mixture as a separate
stream. Preferably, the initiator is added continuously. The
initiator is added at a rate to maintain the polymerization rate,
which rate can be determined by those skilled in the art. The
concentration of the initiator is generally in the range of about
0.01% by weight to about 5% by weight of the total multimonomer
mixture.
The initiator is any free radical initiator known to those skilled
in the art. The initiator includes but is not limited to azo
compounds, peroxides, hydroperoxides, alkyl peroxides,
peroxydicarbonates, peroxyesters, dialkyl peroxides, persulfates,
perphosphates, and the like. Persulfates are the preferred
initiators. The initiator can be employed singularly or in
combination. The initiator can be the same or a different initiator
as is employed to start the polymerization reaction.
The polymerization mixture is continuously or intermittently
agitated by any known method, such as stirring, shaking and the
like. Preferably, the polymerization mixture is continuously
agitated.
The reaction is continued until polymerization has proceeded to the
desired extent, generally from about 40% to about 99% conversion
and preferably from about 70% to about 95% conversion.
The polymerization reaction is stopped by cooling; adding an
inhibitor; such as diethyl hydroxylamine, 4-methoxyphenol and the
like; discontinuing the multimonomer feed mixture; and the like.
The inhibitors and their use are known to those skilled in the
art.
It will be readily apparent to one skilled in the art that the
acrylonitrile olefinically unsaturated multipolymer may be further
modified by the addition of lubricants, dyes, leaching agents,
plasticizers, pseudoplasticizers, pigments, delustering agents,
stabilizers, static control agents, antioxidants, reinforcing
agents such as fillers and the like. It is understood that any
additive possessing the ability to function in such a manner can be
used as long as it does not have a deleterious effect on the melt
characteristics and thermal stability of the high nitrile
multipolymer.
At the conclusion of the polymerization reaction the acrylonitrile
olefinically unsaturated multipolymer is isolated as a solid,
slurry or a latex. Any known technique may be used to isolate the
acrylonitrile olefinically unsaturated multipolymer such as crumb
coagulation, spraying the solution of the multipolymer into a
heated and/or evacuated chamber to remove the water vapors,
stripping, filtration, centrifugation and the like.
The acrylonitrile olefinically unsaturated multipolymer produced by
the process of the instant invention is a high nitrile
thermoplastic multipolymer containing polymerized acrylonitrile
monomer and olefinically unsaturated monomer(s). The multipolymer
comprises about 50% by weight to about 95% by weight polymerized
acrylonitrile and about 5% by weight to about 50% by weight
polymerized olefinically unsaturated monomer(s). The multipolymer
product is homogeneous in that the composition and sequencing of
the multipolymer produced is substantially the same throughout the
process.
The acrylonitrile olefinically unsaturated multipolymer is
thermally stable, melt processable without the addition of any
solvents and homogeneous. The multipolymer of the present invention
may be further processed by spinning, molding, extruding and the
like without the use of solvents. The acrylonitrile olefinically
unsaturated multipolymer possesses excellent thermal, physical and
mechanical properties, can be readily oriented and is homogenous
with short sequences of polymerized nitrile monomer units. Further,
the acrylonitrile olefinically unsaturated multipolymer may be
utilized in numerous applications such as for use as fibers,
sheets, films, pipes, tubings, molded articles and the like.
SPECIFIC EMBODIMENT
The following examples demonstrate the process and advantages of
the present invention.
Equipment
A 1 or 2 liter circulating hot water jacketed reactor was equipped
with a reflux condenser, a thermocouple/controller, a paddle for
agitation, which paddle was set at about 230 rpm to about 250 rpm,
an argon purge tube (continuous), a monomer feed mixture pump and
an ammonium persulfate initiator feed pump.
Components
The overall polymerization components for the examples were as
follows:
______________________________________ Component Grams (gm)
______________________________________ Example 1 Water 1260.0
Rhofac RE-610 12.6 Acrylonitrile (AN) 342.3 .alpha.-Methyl styrene
(MS) 77.7 n-Octyl Mercaptan 8.4 Ammonium Persulfate 1.3 Total:
1702.3 Example 2 Water 1320.0 Rhofac RE-610 17.6 Acrylonitrile (AN)
378.4 Methyl Acrylate (MA) 30.8 Methyl Methacrylate (MMA) 30.8
n-Octyl Mercaptan 8.8 Ammonium Persulfate 2.8 Total: 1789.2 Example
3 Water 1320.0 Rhofac RE-610 17.6 Acrylonitrile (AN) 338.8 Methyl
Methacrylate (MMA) 101.2 n-Octyl Mercaptan 8.8 Ammonium Persulfate
2.8 Total: 1789.2 Example 4 Water 1200.0 Dowfax 8390 (35% active)
45.7 Acrylonitrile (AN) 340.0 Methyl Acrylate (MA) 60.0 n-Dodecyl
Mercaptan 11.2 Ammonium Persulfate 0.8 Total: 1657.7 Example 5
Water 1200.0 Rhofax RE-610 12.0 Acrylonitrile (AN) 344.0 Styrene
(ST) 56.0 n-Octyl Mercaptan 9.0 Ammonium Persulfate 2.5 Total:
1623.5 Example 6 Water 750.0 Dowfax 8390 (35% active) 7.5
Acrylonitrile (AN) 212.5 Vinyl Acetate (VA) 37.5 n-Dodecyl
Mercaptan 7.0 Ammonium Persulfate 1.6 Total: 1016.1 Example 7 Water
1200.0 Rhofax RE-610 12.0 Acrylonitrile 340.0 Methyl Methacrylate
(MMA) 30.0 Vinyl Acetate (VA) 30.0 n-Octyl Mercaptan 8.0 Ammonium
Persulfate 2.5 Total 1622.5
______________________________________
The Rhofac RE-610 is available from Rhone-Poulenc. Dowfax is
available from Dow Chemical Co.
Procedure:
The reactor was pre-charged with water and the surfactant which had
been pre-dissolved at about 50.degree. C. with stirring at about
230-250 rpm (see Table I). The reactor was heated to about
70.degree. C. with continuous argon purging. The initial monomer
charge (see Table II) was added to the reactor. Ammonium persulfate
initiator was added to the reactor to initiate the polymerization
reaction.
The multimonomer feed mixture (see Table III) containing mercaptan
was continuously pumped into the reactor at a constant, fixed
weight ratio of acrylonitrile monomer ("AN") to the olefinically
unsaturated monomer ("X") (see Table VI). Simultaneously, the
ammonium persulfate initiator was pumped into the reactor (See
Table IV). Both the multimonomer feed mixture stream and the
initiator stream were fed into the reactor as separate streams.
Total polymerization reaction time was about 4 to about 6
hours.
After the polymerization reaction was completed the resulting
multipolymer emulsion was filtered through a piece of pre-weighed
cheesecloth to collect and separate any coagulum from multipolymer.
The coagulum was bundled in a cheesecloth and rinsed with warm tap
water. The cheesecloth was dried overnight at about 60.degree. C.
Then the dried cheesecloth/coagulum was weighed. The coagulum was
about nil to about 3% by weight multimonomers. The latexes were
then coagulated in about 1% aluminum sulfate aqueous solution at
about 75.degree. C. to 85.degree. C. with continuous stirring. The
washed and filtered multipolymer crumb was dried for about 3 to
about 24 hours on a vacuum filtered funnel. The multipolymer was
then dried in a fluidized bed dryer at about 55.degree. C. for
about 3 hours. The acrylonitrile, olefinically unsaturated
multipolymer was then analyzed (See Table V and VI).
TABLE I ______________________________________ Aqueous Precharge
Example Water Rhofac RE-blu (gm) Dowfax 8390
______________________________________ 1 1160 12.6 0 2 1220 17.6 0
3 1220 17.6 0 4 1100 0 45.7 5 1100 12.0 0 6 677.5 0 20.0 7 1100
12.0 0 ______________________________________
TABLE II
__________________________________________________________________________
INITIAL MONOMER CHARGE (gm) Olefinically Olefinically Unsaturated
Unsaturated Initiator Acrylonitrile Monomer Monomer Ammonium
Example Mercaptan Monomer X-1 X-2 persuffate (gm)
__________________________________________________________________________
1 2.1 gm n-octyl 21.0 21.0 MS 0 0.71 mercaptan 2 2.2 gm nwyl 37.8
3.1 MMA 3.1 MMA 1.45 mercaptan 3 2.2 gm n-octyl 41.8 2.2 MMA 0 1.45
mercaptan 4 2.8 gm n- 34.0 6.0 MA 0 0.42 dodecyl mercaptan 5 2.24
gm n- 38.0 2 ST 0 1.32 octyl mercaptan 6 1.8 gm n- 13.8 11.3 VA 0
0.53 dodecyl mercaptan 7 2.0 gm n-octyl 34.0 3.0 MA 3.0 MA 1.33
mercaptan
__________________________________________________________________________
TABLE III
__________________________________________________________________________
MULTIMONOMER FEED MIXTURE X.sub.1 X.sub.2 Total Mercaptan* AN
Monomer Monomer Monomer Polymermization Example (gm) (gm) (gm) (gm)
(hrs.)
__________________________________________________________________________
1 6.3 321.3 56.7 MS 0 6 2 6.6 336.6 29.7 MMA 29.7 MA 6 3 6.6 297
99.0 MMA 0 6 4 8.4 306 54 MA 0 4 5 6.76 306 54 ST 0 6 6 5.3 199
26.2 VA 0 5 7 6.0 306 27.0 VA 27.0 MA 6
__________________________________________________________________________
*n-octyl mercaptan was employed in examples 1, 2, 3, 5, and 7.
ndodeceyl mercaptan was employed in examples 4 and 6.
TABLE IV ______________________________________ Aqueous Initiator
Feed Mixture Ammonium Persulfate Example (gms) Water (gms0
______________________________________ 1 0.63 100 2 1.31 100 3 1.31
100 4 0.38 100 5 1.2 100 6 1.1 61 7 1.31 100
______________________________________
TESTING:
Molecular Weight:
The molecular weight (MW) of a multipolymer was determined by Gel
Permeation Chromatography (GPC) in dimethyl formamide solvent and
calibrated with polystyrene standards. This is a known standard
method. The results are presented in Table V.
Glass Transition Temperature:
The glass transition temperature (Tg) was obtained by differential
scanning calorimetry (DSC), A DuPont 1090 instrument was used over
a temperature range from room temperature to 240.degree. C. at a
heating rate of about 5.degree. C./minute under an atmosphere of
nitrogen The results are presented in Table V.
NMR Analysis:
Samples for NMR Analysis were prepared using DMSO-D6 as solvent.
Compositions were determined using .sup.1 H spectra and sequence
distributions were determined using .sup.13 C spectra. .sup.1 H
spectra were obtained using a Varian Gemini 300 Spectrometer at 300
MHz and/or a Varian VXR-400 Spectrometer at 400 MHz. .sup.13 C
spectra were obtained using a Varian Gemini 300 Spectrometer at
75.5 MHz and/or a Varian VXR-400 Spectrometer at 100.7 MHz. The
numerical data is presented in Table VI.
Brabender Plasticorder:
The Brabender plasticorder, available from C. W. Brabender
Instruments Inc., South Hackensack, N.J., is a low shear melt
mixing device that measures the torque (meter-grams, m-g) required
to melt stir a molten polymer. The test determines whether a
polymer may be melted and processed employing standard
thermoplastic equipment. The Brabender analyses were run at about
200.degree. C. with torque readings taken at about 5 minute
intervals to about 30 minutes. This method measures polymer
degradation as a function of time, temperature, and physical
abrading. The numerical data is presented in Table V.
TABLE V
__________________________________________________________________________
Polymer Physical Properties Brabender Brabender Brabender Molecular
Torque Torque Torque Weight m-gm, 200.degree. C. m-gm, 200.degree.
C. m-gm, 200.degree. C. Example Tg (.degree.C.) M.sub.w 10 minutes
20 minutes 30 minutes
__________________________________________________________________________
1 103 50,000 420 420 429 2 81 46,000 653 641 641 3 83 43,000 298
286 298 4 77 62,000 939 996 1115 5 93 43,000 529(220.degree. C.)
550(220.degree. C.) 732(220.degree. C.) 6 90 59,000 900 1329 1836 7
86 48,000 1026 957 992
__________________________________________________________________________
TABLE VI ______________________________________ Polymer Chemical
Properties by .sup.13 C NMR ______________________________________
Composition Monomer Monomer Polymer Example Composition Charge
Ratio (%) Analysis (%) ______________________________________ 1
AN/MS 81/19 76.4/23.6 2 AN/MMA/MA 85/7.5/7.5 83.2/11.2/5.6 3 AN/MMA
75/25 68.5/31.5 4 AN/MA 85/15 85.7/14.3 5 AN/ST 85/15 84.8/15.2 6
AN/VA 85/15 84.6/15.4 7 AN/MA/VA 85/7.5/7.5 87.4/7.7/4.9
______________________________________ Monomer Sequence Example
______________________________________ XXX XXA AXA XAX AAX AAA 1
12.9 43.4 43.7 8.2 48.3 43.5 2 BBA ABA CCA ACA XAX AAX AAA 18.7
81.3 7.9 92.1 2.7 14.8 82.5 XXX XXA AXA XAX AAX AAA 3 0 20.8 79.2 0
31.3 68.7 4 7.5 24.6 67.9 4.0 19.6 76.5 5 16.0 59.9 24.0 1.5 13.1
85.5 6 * * * 3.1 20.2 76.7 7 * * * 2.9 18.3 78.8
______________________________________ A = acrylonitrile B = methyl
methacrylate C = Methyl acrylate X = olefinically unsaturated
monomer *Not measurable by .sup.13 C NMR
Results:
A very uniform and homogeneous acrylonitrile olefinically
unsaturated multipolymer was produced by the process described
herein. The final conversion to multipolymer was about 90% based on
total multimonomers.
The weight average molecular weight of the multipolymer examples
were in the range of about 43,000 to about 62,000.
The Brabender torque data for the examples in the range of about
420 m-gm to about 1026 m-gm at ten minutes and about 429 m-gm to
about 1329 m-gm at thirty minutes. This demonstrates that the
multipolymer is easily melt processed and is thermally stable. The
Brabender torque data is shown in Tables V.
NMR data demonstrated that the sequencing of the multipolymer was
interdispersed and had a high degree of randomness as shown in
Table VI. Further, the polymer analysis demonstrates that the
multipolymer product ratio is similar to the multimonomer feed
ratio.
From the above description and examples of the invention those
skilled in the art will perceive improvement, changes and
modification in the invention. Such improvements, changes and
modifications within the skill of the art are intended to be
covered by the appended claims.
* * * * *